Lactobacillus plantarum Surface-Displayed ASFV (p14.5) Can Stimulate Immune Responses in Mice.

African Swine Fever Virus (ASFV) has spread worldwide, and the lack of vaccines severely negatively impacts the pig industry. In this study, the p14.5 protein encoded by ASFV was used as the antigen, and the p14.5 gene was expressed in vitro using the Lactobacillus expression system. Three new functionally recombinant Lactobacillus plantarum (L. plantarum) were constructed and the expressions of the p14.5 protein, p14.5-IL-33-Mus fusion protein and CTA1-p14.5-D-D fusion protein were successfully detected using Western blot analysis. After oral immunization of SPF mice with recombinant L. plantarum, flow cytometry and ELISA were performed to detect the differentiation and maturity of T lymphocytes, B lymphocytes and DCs of the mice, which were higher than those of the control group. Specific antibodies were produced. The immunogenicity of the adjuvant group was stronger than that of the single antigen group, and the IL-33 adjuvant effect was stronger than that of the CTA1-DD adjuvant.

Ketoenamine Covalent Organic Framework Coating for Efficient Solid-Phase Microextraction of Trace Organochlorine Pesticides.

Fiber coating is a key part of solid-phase microextraction (SPME) technology, and it determines the selectivity, sensitivity, and reproducibility of the analytical method. A ketoenamine covalent organic framework called Tp-Azo-COF with rich electronegative N atoms was prepared as an SPME coating in this work. The Tp-Azo-COF coating had a large surface area of 1218 m2 g-1 and good thermal and chemical stability, and it was applied for the extraction of organochlorine pesticides (OCPs). According to quantum chemistry calculations, the adsorption affinity of the Tp-Azo-COF coating for five OCPs was primarily affected by the halogen bond and hydrophobicity interaction. The extraction efficiencies of the Tp-Azo-COF coating for five OCPs were higher than those of three commercial SPME fiber coatings, and the enrichment factors ranged from 1061 to 3693. When combined with gas chromatography-tandem mass spectrometry, a wide linear range (0.1-1000 ng L-1), low limits of detection (0.002-0.08 ng L-1), and good fiber-to-fiber accuracy (4.3-10.9%) were achieved under optimal conditions. Moreover, the applicability of the developed method was evaluated by analyzing four samples (milk, green tea, tap water, and well water), and the recoveries were in the range of 83.4-101.6%, with relative standard deviations <8.6%. This research extends the application of the stabilized ketoenamine COF as a sample enrichment probe for OCP analysis.

Room-temperature synthesis of magnetic covalent organic frameworks for analyzing trace benzoylurea insecticide residue in tea beverages.

A novel magnetic covalent organic framework (NH2-Fe3O4@COF) was prepared using a simple room-temperature synthesis in this study. These magnetic particles exhibited high adsorption performance with short adsorption time (10 min) for six benzoylurea insecticides (BUs) as magnetic solid-phase extraction (MSPE) adsorbents. Quantum chemistry calculation demonstrated that adsorption mechanism was primarily attributed to strong halogen bonds between electronegative O atoms of COF and electropositive F atoms of BUs as well as potential hydrophobic effect. Wide linearities (10-1000 ng·L-1) and low limits of detection (0.06-1.65 ng·L-1) for six analytes were obtained via liquid chromatography-tandem mass spectrometry. Applicability of the proposed method was further evaluated by analyzing four kinds of original tea beverages. Recoveries of six BUs in spiked samples ranged from 80.1% to 108.4%.

Recent applications of covalent organic frameworks and their multifunctional composites for food contaminant analysis.

Food safety issues are a great concern of the international community. Many methods to analyze and detect food contaminants have been widely researched because both biological and chemical contaminants in food can cause severe damage to human health. Several adsorbent materials have been utilized in the complicated procedure of food sample pretreatment. Covalent organic frameworks (COFs) present enormous application potential due to their tailorable skeletons and pores and fascinating features. In this review, recent applications of COF-based adsorbents for the extraction and analysis of food contaminants, including polycyclic aromatic hydrocarbons, biogenic amines, pesticides, endocrine-disrupting chemicals, heavy metal ions, illegal additives, and biotoxins, from complex samples are summarized. Current challenges and future prospects are also discussed.

Simultaneous separation and determination of eight organophosphorous pesticide residues in vegetables through molecularly imprinted solid-phase extraction coupled to gas chromatography.

How to determine the multipesticide residues in vegetables is an important problem. In this study, a new molecularly imprinted polymer was synthesized using O,O-dimethyl thiophosphoryl chloride, an intermediate for the manufacture of organophosphorous pesticides, as the template. Characterization test indicated that the synthesized polymer exhibited good recognition and selectivity for dichlorvos, methamidophos, acephate, folimat, monocrotophos, parathion-methyl, phosphamidon, and malathion. A molecularly imprinted SPE coupled to GC for simultaneous separation and determination of eight organophosphorous pesticides residues was developed. Under optimal conditions, the linear range of this method was 0.001-10.0 mg/L. The LOD of this method was in the range of 0.13-0.90 µg/kg. With a flow rate of 2.5 mL/min for loading 100 mL, the enrichment factor in the range of 25-480 for the eight organophosphorous pesticides was obtained. The RSD of the eight organophosphorous pesticides based on five replicates was from 1.50 to 4.09%. The accuracy of the proposed method was evaluated by recovery measurements on spiked samples, and good recovery rates ranging from 80.11 to 97.70% were achieved. Moreover, this method was evaluated for the quantitative detection of eight organophosphorous pesticide residues in leek and pakchoi samples.

Study of an online molecularly imprinted solid phase extraction coupled to chemiluminescence sensor for the determination of trichlorfon in vegetables.

This study reports a new online molecularly imprinted solid phase extraction coupled to chemiluminescence for the determination of trichlorfon. This molecularly imprinted polymer (MIP) was prepared through bulk polymerization, in which methacrylic acid (MAA) was used as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. This novel functionalized material was characterized by FT-IR spectra and adsorption, and it exhibited good recognition and selective ability and fast adsorption-desorption dynamics toward trichlorfon. The factors affecting preconcentration of the analytes and sensitivity of the method are discussed in detail. Under the optimal condition, the linear range of the calibration graph was between 0.02 and 1.0 ng L(-1), and the detection limit was 1 × 10(3) ng L(-1). The blank cucumber samples spiked with trichlorfon at three levels were extracted and determined by the presented method with recoveries ranging from 83.5 to 94.5%, and the results were correlated well with those obtained using gas chromatography. Moreover, this developed method was successfully applied to the quantitative detection of trichlorfon residues in leek samples.

[Macrozoobenthos functional groups in intertidal flat of northwest Jiaozhou Bay].

Based on the survey of macrozoobenthos at 35 locations of 7 sections in the intertidal flat of northwest Jiaozhou Bay in February, May, August, and November 2009, three zones including high tidal zone (A), mid tidal zone (B, C, and D), and low tidal zone (E) were selected to study the functional groups of macrozoobenthos in the flat. A total of 71 macrozoobenthos species were recorded, most of which were of mollusk (31 species), polychaete (20 species), and crustacean (14 species). The species number in A, B, C, D, and E was 26, 33, 35, 38, and 31, respectively. According to their food preferences, the macrozoobenthos were classified into 4 functional groups, i. e., planktonphagous, carnivorous, omnivorous, and detritivorous. The percentage of the species number of each functional group in the total species number of macrozoobenthos was in the order of carnivorous > planktophagous > detritivorous > omnivorous. Carnivorous group had the highest species diversity index, while omnivorous group had the lowest one. Overall, the species richness index, evenness index, and species diversity index were higher in mid tidal zone and lower in high and low tidal zones. The present study showed that the distribution of macrozoobenthos functional groups varied with the environment of tidal zones, being an integrative reflection of their habitat conditions.